(a) Field of the invention:
The present invention relates to a sucking pipe for potable water, etc., and more specifically to a two-stage type of freely elongatable sucking pipe made of synthetic resin.
(b) Description of the prior art:
Conventionally, there has already been known a two-stage type of freely elongatable sucking pipe consisting of a larger-diameter pipe member and a smaller-diameter pipe member so combined as to be shortened for convenient storage, carriage, transportation, attachement to vessels of beverage, and elongated for sucking.
Such a two-state type of freely elongatable sucking pipe is generally so designed as to assure close contact partially between the inside surface of the larger-diameter pipe member and the outside surface of the smaller-diameter pipe member, thereby preventing either pipe member from shifting or dropping by its own weight in use.
Further, such a two-stage type of freely elongatable sucking pipe must not allow leakage of breath or sucked liquid during suction. For this purpose, contact between the inside surface of the larger-diameter pipe member and the outside surface of the smaller-diameter pipe member must be as close as possible.
However, it is rather hard to assure perfectly close contact between the larger-diameter pipe member and the smaller-diameter pipe member.